Three-roller mill



(No Modl.) 4 Sheets-Sheet 1.

J. L. WILLFORD.

THREE ROLLER MILL.

Patented Nov. 27, 1888. Fig.1-

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- J. L. WILLFORD.

THREE ROLLER. MILL.

N0. 393,681L Patented NOV. 27, 1888.

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J. L. WILL-FORD.

THREE ROLLER MILL.

- Patented Nov. 27,1888. 12: 5.

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I THREE ROLLER MILL. No. 393,681. Patented Nov. 27-, 1888.

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N. PETERS. PhMu-Lilhnmphu. Wiihingwl. D C.

1 UNITED STATES j PATENT O FICE.

JOSEPH L. WILLFORD, OF MINNEAPOLIS, MINNESOTA.

THREE-ROLLER MILL.

SPECIFICATION forming part of Letters Patent No. 393,681, dated November 27, 1888.

Application filed January 25, 1856. Serial No. 189.579. (No model.)

To all whom, it may concern.-

Be itknown that I, J osnrrr L. WILLFORD, of Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain Improvements in ThreeRoller Mills, of which the following is a specification.

This invention relates to improvements in roller-mills forgrindinggrain,and particularly to that class in which three rolls are used, one being in grinding contact with each of the others; and the objects I have in view are to provide a machine of this class of simple construction and large capacity, and also to provide an improved casing for a roller-mill.

My invention consists, generally, in the constructions and combinations hereinafter described, and particularly pointed out in the claims.

'In the accompanying drawings, Figure l is a side elevation of the mill; Fig. 2, an elevation of the opposite side; Fig. 3, a vertical section of the hopper, rolls, and easing; Fig. 4, an elevation of the main casing; and Figs. 5, 6, and 7 are details.

In the drawings, 2 represents .the main frame or casing of the machine, and 4 is the casing in which are located the hopper and feed-roll. The main casing (see Fig. 4) is preferably cast in one piece, and the casing 4 is of wood and suitably secured to the casing 2. The main casing has an opening, 20, through each side wall, which is preferably of substantially circular form, with offsets 22 24: at the upper and lower parts to receive the journals of the top and bottom rolls, as shown in Fig. 4. The upper and lower rolls, 8 and 10, are first put into the casing through the center opening, 20, in the wall, and thenmoved into the offsets 22 24, that receive their journals. The center roll, 3, is then put in place between the other rolls, and metal covering, plates 5 Sam bolted to the casing, covering the openingsinthe walls. The openings areformed in the opposite walls of the casing in order that the rolls may beinserted or removed from either side, as the mill will often be used in positions where the rolls could not be removed if the openings were formed in one side only, and by this construction I am enabled to insert all of the rolls through an opening that is only of sufficient size to admit the largest one of them. This could not be done unless the openings were formed in both walls.

Offsets 22 and 24, it will be understood, are parts of the opening 20, and while I prefer to form the opening with these offsets it will be seen that as an equivalent construction the openings themselves may be made large enough to include the offsets, so that the upper and lower rolls, or either of them, may be inserted through the opening 20, and then moved laterally a sufficient distance to permit the other roll to be inserted through the same opening, and so longas the opening 20 islarge enough to permit the roll or rolls first inserted to be moved in the casing far enough to admit a of the insertion of the other rolls its form is immaterial, although I consider the opening having the offsets-of sufficient size to receive the journals of the rolls first inserted to be preferable.

The journals 6 of the center roll, 3, are mounted in boxes 7 in the plates 5, the plates being provided with the ribs 9, that strengthen them and form supports for the boxes.

The upper and lower rolls are each journaled in boxes, that arQ-carriedby levers l5 l7, pivoted at the sides of the casing above and below the journals of the center roll. These levers extend diagonally to the front of the casing, on each side thereof, as shown in Figs. 1 and 2. The upper lever has one journal half-box, 18, formed on its under side, and a cap, 19, bolted to it beneath the half-box 18. In these boxes the journals of the upper roll are supported. The lower lever has a similar half-box, 21, formed on its upper side and a cap, 23, bolted to it. In these boxes the journals of the lower roll are supported.

A vertical bolt, 25, extends through the ends of each pair of levers. It is threaded at its upper end and provided with a threaded hand-wheel, 27. A washer-plate, 29, is placed under the hand-wheel 27, and between this washer and the upper lever isa coiled spring, 31. A shaft, 83, extends across the front of the casing between the ends of the levers, and has at each end a double eccentric, 35.

Bearing-blocks 37 are secured to the faces of the levers in position to be in contact with the eccentrics. These blocks are secured to the levers by screws 39 and adj usting-nuts 41.

As the block 37 on each lever is independent, by adjusting these blocks an independent adjustment of the ends of the rolls to secure their parallelism is obtained.

The shaft 33 is provided at one end with an operating-lever, 43, by means of which it may be turned and the ends of the levers forced apart by the eccentrics, thereby moving the upper and lower rolls from the center roll. The lever 43 is preferably provided with the arm 45, that projects below the shaft. A setscrew, 47. extends through a ing, 49, and bears against the arm 45. By turning this screw the adjustment of the rolls may be regulated. Ihe rolls may be separated by the lever and returned to the same adjustment. The tension of the springs 31 determines the pressure ofnthe upper and lower rolls upon the center ro The pivots for the lovers are formed upon the ends of square or flat-sided bars, 53, which extend through bosses 55, formed on the outer sides of the casing. (See Fig. 4.) Setscrews 51 are tapped through each of these bosses. The ends of these screws bear against the flat sides of the bars 53, and by means of these screws the pivots of the lovers may be adj usted. Clamping screws 57 are tapped through the bosses and bear against the bars.

A driving-pulley, 50, is mounted on the shaft of the center roll, and through this pulley power is applied to drive this roll. As the surface of the center roll is close to the surfaces of the upper and lower rolls, these rolls are driven by the friction from the center roll when the material is passing through the mill, and would have the same surface speed as the center roll. To prevent this I provide an independent differential belt-drive, by which the upper and lower rolls are held at a slower surface speed than the center roll. Upon the shaft of the center roll is a pulley, 61. This pulley is located, as shown in the drawings, on the opposite end from the driving-pulley. In some instances I prefer to provide the differential belt-drive on each side of the casing when it will be located at one side inside the driving-pulley. A pulley, 65, is mounted on the shaft of the upper roll, and a similar pulley, 67, on the shaft of the lower roll. These three pulleys are preferably all of the same diameter.

A lever, 71, is pivoted to the side of the easing in the plane of the pulleys, and has a hole through its upper end,throngh which passes a threaded bolt, 73. A coiled spring, 75, is arranged on this bolt between the lever and the head of the bolt. A bracket, 77, is bolted to the side of the casin g, and through this the bolt extends. A hand-wheel nut, 79, is arranged on this bolt and bears against the bracket. An idler, S1, is journaled on this lever. A belt, 83, passes around the pulley on the center roll, around each of the other pulleys and around the idler-pulley on the tightener, substantially as shown in Fig. 2.

I form the lever 71 in two parts, one part, 72, being pivoted to the casing and the other part being formed with a journal, 70, that fits into a socket, 74, in the part 72. A set-screw, 76, is provided for clamping the parts together. By this means the lever can be turned axially to bring the belt into alignment with the pulleys.

' In Figs. 5 and 6 I have shown a preferable construction of tightener, by means of which I am able to lead the belt in either direction, as desired.

The journal-box S0, for each journal of the idler-pulley, is formed independently of the lever, and provided with a bolt, 82, which passes through a slot in the lever, the lever being open at the center and the belt passing therethrough. Eitherjournal of the tightenerpulley may be adjusted lengthwise of the lever, and thereby any desired lead may be given to the belt. By turning up the handwhccl 79 the belt is tightened over the pulleys, the tightener holding the belt with a spring tension. \Vhen the pulleys are of the same diameter the journals ofthe three rolls will have the same speed, and the speed of their grind ing-surfaces will be proportioned to their cireumferences. \Vhen three roller mills are made with the grinding-rolls of the same diameter, their centers are brought so near together that it is impracticalile, if a differential speed is desired, to use a differential belt-drive, as it is impossible to place a suitable pulley on the center roll and belt from it to the other rolls without locating the pulleys in different planes and using the idlers to twist the belts.

By using a center roll of large diameter I am able to place the pulleys in the same plane and to use an open untwistcd belt for connecting them. I am also able to use pulleys of equal diameter on the three rolls. I provide cant boards or blanks 85 87 for directing the material from the hopper between the top and center rolls, and from these rolls between the lower and the center roll.

In some instances I provide a perforated cant-board, 87, as shown in Fig. 7, which acts as a screen and permits the fine material to pass through it, and directs the coarse material between the lower rolls. I prefer to arrange the rolls, as shown in Fig. 3, with the center of the upper roll over the center of the lower roll, but with the centers of these rolls at one side of the center of the other roll. By this arrangement the belt-pulleys are brought into such position that I get a large wrap of the belt around them, and am therefore able to firmly hold the differential speed. By this arrangement of the large center roll, with the upper and lower rolls located at one side of its center, I am able to use the perforated cantboard, or to use separate spouts for spouting material to the center and upper roll and to the center and lower roll.

The hopper 91 is provided with an ordinary feed-roll, 93, and with an adj nstable feed-gate,

IIO

95. I also provide a cut-off,by means of which the feed can be stopped without changing the adjustment of the feed-gate. This cut-ofi' consists of a plate, 97, preferably metal, that is adapted to set across the lower part of the hopper and form a tight bottom therein. This cut-off is mountedon crank-arms 99, having studs 101, that are journaled in the walls of the hopper. A lever, 102, is fastened to one of these studs outside of the casing. By turning this lever the cut-off can be moved from the position shown by full lines in Fig. 3 to the position shown by dotted lines in the same figure, in which the board is parallel with the wall of the hopper and does not obstruct the feed. When the mill is used for the first reduction of wheat, I may use the perforated cant-board, and create an upward current of air through it to take away the dirt loosened in the first break made by the upper and center rolls. For this purpose a cant-board formed of a series of overlapping slats might be used as the equivalent of the perforated cant-board.

I claim as my invention 1. The combination, with the center roll, of the pivoted levers carrying the upper and lower rolls and provided with the bearingblocks 37, the shaft 33,provided with the double eccentric 35, arranged between said bearing-blocks, the rods 25, passing through said levers, the springs 31 on said rods, and the nuts 27, all substantially as described.

2. The combination, in a roller-mill, of a casing provided with openings in its opposite walls, through either of which all of the rolls may be inserted or removed, a roll having its journals extending through said openings and mounted in movable bearings, and a roll having itsjournals extending through said openings and mounted in fixed bearings, substantially as described.

3. In a three-roller mill, the cast-metal casing having in its opposite walls the openings through which the rolls may beinserted or removed and the offsets 22 24. in the upper and lowerparts of said openings, adapted to receive thejournals of the upper and lower rolls, in combination with the rolls and roll-bearings, as set forth.

4. The combination, in a threeroller mill, with the casing having openings in its opposite walls, through either of which all of the rolls may be inserted or removed, of the upper and lower rolls, the center roll, and the pivoted levers receiving the journals of the upper and lower rolls, and the plates covering the openings in the casing and having journalboxes receiving the journals of the center roll, substantially as described.

5. The combination, in a roller-mill, of a casing provided with openings in its opposite walls,through which the rolls maybe inserted or removed, plates secured to said casing and partly covering said openings, a roll having its journals extending through said openings and mounted in bearings in said plates, and a roll having its journals extending through the uncovered parts of said openings and mounted in movable bearings, substantially as described.

6. The combination, in a roller-mill, with the belt-pulleys and belt, of the tightener-lever, the idler-pulley, the independent jourrial-boxes supporting said pulley, and means for adjusting either of said boxes longitudinally on said lever, for the purpose set forth.

7. The combination,ina three-roller mill, of a casing provided with openings in its oppo site walls, through which the rolls may be inserted or removed, plates partly covering said openings, the center roll having its journals extending through said openingsand mounted in said plates, the upper and lower rolls having their journals extending through the uncovered portions of said openings, and pivoted levers in which said upper and lower rolls are mounted.

8. In a roller-mill, a casinghaving openings in its opposite walls, through which the rolls may be inserted or removed and an offset from each of said openings,adapted to receive a rolljournal, in combination with plates covering said openings, a roll having its' journals arranged in said offset, and a roll having its journals extending through openings in said plates.

9. The combination, in a roller-mill, with the belt-pulleys and belt,of the two-part tightenerlever pivoted upon the mill-casing and having one part axially pivoted upon the other, the idler-pulley, the journal-boxes mounted upon the axially-movable portion of the tightener lever and supporting said pulley, and means for independently adjusting either of said boxes longitudinally on said lever, substantially as described.

In testimony whereof I have hereunto set my a In presence of A. 0. PAUL, R. H. SANFORD. 

